One of the most difficult diagnostic problems is separating the effects of MTBI and post-traumatic stress disorder (PTSD), because signs and symptoms of these conditions often overlap. Early and accurate diagnosis of MTBI and its differentiation from both acute stress disorder (ASD) and PTSD are a major priority for military medicine due to overlap in symptoms (e.g., attention problems) and the frequent lack of external signs or even self-awareness of MTBI, especially in association with blast injury.